Celtic bounced back from the disappointment of their Old Firm defeat on Saturday in style by picking up a point in the Nou Camp against Barcelona following a battling performance.
The Hoops are still in with a chance of qualifying for the UEFA Cup thanks to a 45th minute equaliser from John Hartson after Samuel Eto'o had put Barca ahead midway through the first half.
Barcelona dictated the early play showing confidence in possession and denying Celtic any chance of a shot on goal.
The midfield duo of Ronaldinho and Silvinho looked particularly dangerous and Joos Valgaeren, charged with marking Ronaldinho, was nutmegged twice by the Brazilian in the opening ten minutes.
Barcelona's best early chance in front of goal came on 15 minutes when Eto'o had a 25-yard shot blocked on the line by Magnus Hedman.
Five minutes later Celtic had a rare shot on goal as Alan Thompson tried his luck from nearly 30 yards out but his attempt was easily gathered by the Barcelona keeper.
Eto'o finally opened the scoring in the 24th minute. He exchanged passes with Deco on the edge of the area before firing low into the net under Hedman to make it 1-0.
From this point it seemed almost certain that Barcelona would cruise to a win. Less than a minute after his goal Eto'o side-footed a Ronaldinho cross narrowly wide and Barcelona showed no signs of easing the pressure on the visitors.
But they were left to regret those missed chances when Celtic came up with an equaliser from nowhere with almost the last kick of the first half.
Chris Sutton was brought down by Presas Oleguer and won a free-kick in a dangerous position. Stilian Petrov's set-piece found Hartson at the back post and he flicked the ball in to make it 1-1 despite the pleas of the Barcelona fans who believed the Welshman was offside.
The goal boosted Celtic who started the second half much more confidently than they had the first.
But Barcelona, who only needed to pick up one point going into the match to guarantee their place in the next stage of the Champions League, could afford to be patient, and never looked like being beaten.
Midway through the half substitute Andres Iniesta saw his header well saved by Hedman and two minutes later Ronaldinho blasted his shot straight into the Celtic defenders.
But Celtic held on to secure a spectacular draw and thanks to AC Milan's victory over Group F rivals Shakhtar Donetsk, Martin O'Neill's men can still qualify for the UEFA Cup.